Conveying apparatus



NOV. 18, 1969 A, WARD 3,479,092

CONVEYING APPARATUS Filed Feb. 7, 1968 48- 50 46 44 50 asf l2 O o l 3 LAL., /42

F IG. 2o (7% N 24 1 seks-rho 3e L56 36j/ 58) United States Patent 3,479,092 CONVEYING APPARATUS Alan Ward, 160 Clearview Drive, East Greenwich, R.I. 02818 Filed Feb. 7, 1968, Ser. No. 703,656 Int. Cl. B65g 51/02 U.S. Cl. 302-29 11 Claims ABSTRACT OF THE DISCLOSURE The present invention relates generally to conveying apparatus and specifically to apparatus which is adapted to introduce pressurized fluid -between an article and a surface over which the article is to be moved.

In recent years, various devices have been demonstrated which employ pressurized fluid as a medium for supporting a vehicle or other article above a surface. This method has also 'been suggested for application to material handling apparatus. In some of these applications, fluid is directed continuously through a series of apertures in a surface over which an article is to be moved so as to form a film or cushion of air to support the article. Such systems, however, are wasteful of fluid and for that reason are very costly in their operation. For improved economy other systems have suggested the use of a movable valve which is sensitive to the presence of an article being moved and effective only during the presence of the article to introduce fluid between the article and the surface over which the article is being transported. These others systems, however, are somewhat limited because movable valves are subject to sticking or binding; furthermore, their speed of operation is limited by the inertia of the moving part.

The present invention incorporates the features of the two systems just noted while avoiding their drawbacks. To this end, the invention has no moving parts, yet admits pressurized fluid between an article being transported and the surface over which it is moving only in the presence of the article, being inactive during its absence. Specifically, an actuating unit including a fluid amplifier is located -beneath the surface which defines a path of movement for the article. The fiuid amplifier includes a passage connecting a source of pressurized fluid to an exhaust channel, and first and second conduits, each communicating with the passage and emerging respectively at first and second ports in the surface over which the article is to be moved. The -first and second conduits are so positioned relative to the passage that as the article moves along the surface and covers the second port, pressurized fluid already present between the article and the surface from a previous actuating unit is directed into the second conduit and impinges on the fluid flowing in the passage. This causes the fluid flowing in the passage to be deflected so that it no longer fiows to the exhaust channel but instead is directed into the first conduit and exits from the first port, thereby creating a cushion or film of fluid for the oncoming article. When the article has passed over the second port, fluid is no longer directed into the second conduit to impinge on the fluid flowing in the passage. When this occurs, the fluid flowing in the passage is no longer dievrted into the first conduit but returns to its ICC original course such that it once again ows to the exhaust channel.

An object of the present invention is to provide new and improved conveying apparatus.

Another object of the invention is to provide new and improved conveying apparatus which is operable to introduce pressurized fiuid between an article and the surface over which the article is to be moved. A related object is to provide such apparatus which introduces pressurized uid into a region above the surface only in the presence of the article. Another related object is the provision of such apparatus which employs no moving parts.

A further object of the invention is the provision of conveyor apparatus employing a fluid amplifier which is responsive to the presence of the article over a surface for introducing fluid from a source into a region between the article and the surface for supporting the article. A related object is the provision of such apparatus wherein the fluid amplifier includes a discharge conduit operable for introducing fluid from a source into the region for supporting the article and a control conduit responsive to the presence of the article over the surface for operating the discharge conduit.

Still another object of the invention is the provision of a plurality of fluid amplifiers communicating with the surface over which an article is to be moved, each amplier being operable to introduce fluid between the article and the surface in the presence of the article but inoperative to introduce fluid when the article is no longer present.

Other and further objects and advantages of the invention will be apparent or will be set forth in greater detail in the description which follows, taken together with the accompanying drawings in which like numerals refer to like parts throughout.

In the drawings:

FIG. 1 is a perspective view, partly cut away and in section of conveying apparatus embodying the present invention, certain parts removed for clarity;

FIG. 2 is an exploded view of an individual actuating unit used by the conveying apparatus of FIG. 1;

FIG. 3 is a top plan view of a part illustrated in FIG. 2;

FIG. 4 is a schematic longitudinal section View taken through the conveying apparatus shown in FIG. 1 and illustrating one position of an article being moved; and

FIG. 5 is a schematic sectional view similar to FIG. 4 and illustrating another position of the article.

Refer now to the drawings and in particular to FIG. 1 in which an article 10 is shown as it is moved along an upper surface 12 of a conveyor 14. The conveyor 14 is equipped with suitable sidewalls 16 for guiding the article 10 as it advances along the upper surface 12. To support the article 10 on the upper surface 12 and to enable it to be easily moved by any suitable mechanism (not shown) along the conveyor 14, a plurality of actuating units 18 are suitably mounted in recesses 20 provided at spaced intervals along the conveyor 14. Under appropriate conditions, as will be discussed shortly, each actuating unit is activated to introduce pressurized fluid between the article 10 and the surface 12 to an extent sufficient to support the article and to permit its movement in a substantially frictionless manner along the conveyor 14. For purposes of illustration, two rows of the actuating units 18 are illustrated in FIG. 1 such that the units in one row are staggered relative to those in the other row thereby providing a substantially continuous support cushion of pressurized fluid as the article 10 is advanced along the upper surface 12.

Turn now to FIG. 2 in which the detailed construction of each actuating unit 18 is most clearly shown. Each actuating unit 18 includes upper and lower mating blocks,

22 and 24 respectively, and when assembled, the upper block 22 rests firmly against the lower block 24 so that a peripheral rim 26 on the latter firmly engages with a mating peripheral shoulder 28 on the former. Suitable fasteners such as screws 30 extend through clearance holes 32 in the upper block 22 and are threadedly received in threaded holes 34 in the lower block 24.

Suitably formed in the lower block 24 (see especially FIG. 3) is a fluid amplier 35 preferably of the monostable variety which includes a curved passage 36 extending from one side of the lower block 25 to the other side, and branching off from opposite sides of the passage 36, respectively, a rst or discharge conduit 38 and a second or control conduit 40. A pair of extension conduits 42 and 44 are located in the upper block 22 and respectively terminate at first and second apertures 46 and 48 in an outer face of the upper block 22. The first aperture 46 therefore communicates with the discharge conduit 38 and similarly the second aperture 48 communicates with the control conduit 40 when the actuating unit 18 is in the assembled condition.

When an assembled actuating unit 18 is mounted in its associated recess 20 such that an outer face 50 of the actuating unit 18 is substantially coplanar with the upper surface 12 of the conveyor 14, opposite ends of the passage 36 are aligned with holes 52 and 54 (FIG. l) in the walls 56 which together with walls 57 define the recess 20. Each of the holes 52 communicates with a supply channel 58 which serves as a source of pressurized fluid such as air and each hole 54 communicates with a return channel 60 which serves as an exhaust for the pressurized fluid. In FIG. 1, it is noted that the supply channels 58 and exhaust channels 60 extend parallel to one another for the length of the conveyor 14.

Thus, with an actuating unit 18 in its operating position, pressurized fluid normally flows from the supply channel 58 through the hole 52, then via the passage 36 and the hole 54 into the return channel 60. To prevent leakage of the fluid at the interfaces between the ends of the passage 36 and the holes 52 and 54, O-rings 62 are received in suitable circular grooves 64 in the sides of the actuating unit 18 and these bear against the walls 56 when the actuating unit 18 is mounted in place within the recess 20. The passage 36 is suitably shaped to assure that fluid flowing from the supply channel 58 normally adheres closely to an arcuate surface 66 at a side of the passage 36 nearest the viewer (FIG. 3). This tendency of fluid to remain attached to a surface is technically known as the Coanda effect.

The operation of the invention will now be described with particular reference to FIGS. 4 and 5. As the article is suitably moved along the upper surface of a conveyor 14 in the direction of an arrow 68, it eventually reaches a position at which, still being supported by fluid from a previous actuating unit 18, it overlies a second aperture 48 (FIG. 4) of a succeeding actuating unit 18. When this occurs, the fluid under pressure beneath the article 10 is directed downwardly via the extension conduit 44 into the control conduit 40 and is effective to divert the pressurized fluid normally proceeding from the supply channel 58 to the return channel 60 into the discharge conduit 38. In this manner, pressurized fluid from the supply channel 58 is directed outwardly via the extension conduit 42 through the first aperture 46 in preparation for the arrival of the article 10. When the article 10 is moved to a position as indicated in FIG. 5 at which it no longer overlies the second aperture 48 of the previous actuating unit 18, pressurized fluid is no longer directed downwardly and into the control conduit 40. Since the fluid amplifier 35 is preferably of the monstable variety, the cessation of fluid flow into the control conduit 40 has the result that fluid from the supply channel 58 is no longer diverted into the discharge conduit 38, but returns to its original course adhering closely to the arcuate surface 66 and flows finally into the return channel 60.

Therefore, it is readily apparent that the invention, as

disclosed, operates according to the manner set forth in the introduction of this disclosure. Specifically, the invention employs no moving parts and is operative only in the presence of an article 10. The actuating units 18 are inexpensive to produce and require a negligible amount of maintenance, are highly reliable, are uneffected by temperature, and are unhurt by heavy vibrations or shock. A further advantage resides in the ability to remove an actuating unit 18 in the event it should become clogged with foreign material or should it be desirable to replace the actuating unit for any other purpose.

While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made without departing from the spirit and scope of the invention.

What is claimed is:

1. Conveying apparatus comprising: a source of pressurized fluid, a surface over which an article is to be advanced, and actuating means having no moving parts responsive to the presence of the article over said surface for introducing fluid from said source into a region between the article and said surface for supporting the article.

2. Apparatus as set forth in claim 1 wherein said actuating means includes discharge means operable for introducing fluid from said source into said region for supporting the article and control means responsive to the presence of the article over said surface for operating said discharge means.

3. Apparatus as set forth in claim 2 wherein said actuating means includes a passage connected with said source and having an exhaust port for normally exhausting fluid from said source, said discharge means includes a first conduit connected with said passage and communicating with said region at a first port in said surface, and said control means includes a second conduit connected with said passage and communicating with said region at a second port in said surface spaced from said first port whereby the presence of the article over said second port is effective to deflect fluid from said source away from said exhaust port and into said first conduit for introduction into said region for supporting the article.

4. Appartus as set forth in claim 3 wherein said passage includes an arcuate surface against which fluid flowing from said source toward said exhaust port normally flows, said second conduit communicating with said passage at said arcuate surface, and said first conduit communicating with said passage opposite said arcuate surface whereby the presence of the article over said second port is effective to deflect the flow of fluid from said source away from said arcuate surface and into said 4first conduit for introduction into said region for supporting the' article.

5. Apparatus as set forth in claim 1 wherein said actuating means includes a fluid amplifier having a passage with an exhaust port for normally exhausting fluid from said source, a first conduit connected with said passage and communicating with said region at a first port in said surface, and a second conduit connected with said passage and communicating with said region at a second port in said surface spaced from said first port, whereby the presence of the article over said second port is effective to deflect `fluid from said source away from said exhaust port and into said first conduit for introduction into said region for supporting the article.

6. Apparatus as set forth in claim 5 wherein said passage includes an arcuate surface against which fluid flowing from said source toward said exhaust port normally flows, said second conduit communicating with said passage at said arcuate surface, and said first conduit communicating with said passage opposite said arcuate surface whereby the presence of the article over said second port is effective to deflect the flow of fluid from said source away from said arcuate surface and into said first conduit for introduction into said region for supporting the article.

7. Material handling apparatus comprising: a surface over which an article is to be advanced, a source of pressurized fluid, a plurality of stationary actuating means operable for introducing fluid from said source into a region between the article and said surface for supporting the article, each of said actuating means including a passage having an exhaust port for normally exhausting fluid from said source, a rst conduit connected with said passage and communcating with said region at a rst port in said surface, and a second conduit connected with said passage and communicating with said region at a second port in said surface spaced from said first port, whereby the presence of the article over said second port is effective to deflect fluid from said source away from said exhaust port and into said lirst conduit for introduction into said region for supporting the article.

8. Apparatus as set forth in claim 7 wherein said passage includes an arcuate surface against which fluid flowing from said source toward said exhaust port normally flows, said second conduit communicating with said passage at said arcuate surface, and said first conduit communicating with said passage opposite said arcuate surface whereby the presence of the article over said second port is effective to deflect the flow of fluid from said source away from said arcuate surface and into said first conduit for introduction into said region for supporting the article.

9. Conveying apparatus comprising a surface over which an article is to be advanced, a supply channel beneath said surface providing a source of pressurized fluid, a return channel beneath said surface providing an exhaust for said pressurized fluid, a plurality of recesses in said surface communicating with said supply channel and with said return channel, and actuating means having no moving parts removably mounted in each of said recesses,

each of said actuating means including an outer face which is coplanar with said surface when mounted for operation in its associated one of said recesses, and responsive to the presence of the article over said surface for introducing fluid from said source into a region between the article and said surface for supporting the article.

10. Apparatus as set forth in claim 9 wherin said actuating means includes a passage connected with said source and having an exhaust port for normally exhausting fluid from said source, a first conduit connected with said passage and communicating with said region at a first port in said surface, and a second conduit connected with said passage and communicating with said region at a second port in said surface spaced from said rst port whereby the presence of the article over said second port is effective to deflect fluid from said source away from said exhaust port and into said first conduit for introduction into said region for supporting the article.

11. Apparatus as set forth in claim 10 wherein said passage includes an arcuate surface against which fluid flowing from said source toward said exhaust port normally flows, said second conduit communicating with said passage at said arcuate surface, and said first conduit communicating with said passage opposite said arcuate surface whereby the presence of the article over said second port is effective to deflect the flow of fluid from said source away from said arcuate surface and into said first conduit for introduction into said region for supporting the article.

References Cited UNITED STATES PATENTS 2,785,928 3/1957 Hanson 302-17 3,272,415 9/ 1966 Wallin 302-29 3,279,863 10/ 1966 Bouladon et al. 302-29 ANDRES H. NIELSEN, Primary Examiner 

